Automatic speed control device



Feb. 7, 1939. c. HoLT AUTOMATIC SPEED CONTROL DEVICE 2 Sheets-Sheet l Filed Feb. 7, 1938 Sv bv INVENTDR. W BY s@ MVM W ATTORNEYS.

Feb. 7, 1939. c. HOLT 2,145,070

AUTOMATIC SPEED CONTROL DEVICE Filed Fem?, 1938 2 sheets-sheet 2 il o 64 V* 6 j l' o p 5 65 5%/ .39 65 5 59 5@ 9 37 60. O C' "u s y 66 50 '50. 54?53 I 5354' jl- L45 43 Z 3 JNVENmR MM 4 4Z n 4/7 39 BY MVN-W 4 4, 44 Amie/ways.

Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE 9 Claims.

My invention relates to automatic speed control devices for internal combustion engines.

An object of the invention is to provide an I emcient and highly sensitive controlling device l which will automatically positively maintain the engine speed (R..P. M.) at a substantially constant predetermined manually xed rate regardless of variations in load.l

Other objects and advantages of the invention will be understood the description is considered with the accompanying drawings, in which:

Figure 1 is a side elevation of my improved speed control apparatus;

Figure 2 is an enlarged plan view of the governor with the housing cover removed;

Figure 3 is an enlarged vertical section through the governor;

Figure 4 is a fragmentary detail of the intake manifold and valve operating means; and

Figure 5 is a section on the line 5-5 of Figure 3.

Referring more particularly to the drawings, I denotes a conventional internal combustion engine for automobiles, trucks and the like, on

which my control device or system is installed, only the upper part of the engine being shown. Gasoline is fed in any suitable manner to a carburetor 2, mounted on an intake manifold 3, by means of a gasoline line 4, leading fromagasoline tank, not shown. Communication between the carburetor and the intake manifold is'controlled by a butterfly throttle valve 5, in turn operatively connected with a hand throttle 6 and a foot accelerator 1.

The automatic control device-comprises a plurality of interconnected hydraulic cylinders 9, I0 and I I, which get their supply of hydraulic uid froms a supply tank or reservoir I2, and which directly or indirectly influence the movements of -4'0 the carburetor valve 5, in a manner hereinafter 50 supply and branch pipes with respect to the re' spective cylinders is such that uid I6 will flow by gravity from the reservoir I2 into the cylinders when shut off valve I1 is open, thus insuring that any leakage loss in the system will be auto- 55 matlcally replenished.

(Cl. 12S-108) The piston I8 of cylinder 9, which may be termed the master cylinder, is operatively connected to the foot pedal or accelerator 1, through the medium of a pedal rod I9, attached at one end to the pedal and at its other end adjustably 5 secured to one end of a turn buckle 25, the other end of the latter being pivoted to the piston rod 20 of piston I8. A heavy coil spring 2I, on piston rod 20 seating at opposite ends against cylinder 9 and a collar 22, tends to pull the piston l0 I8 and rod 20 outwardly or against the pressure of the foot accelerator. The piston 23 of cylinder I0 is connected through its piston rod 24 with the buttery valve 5 which controls the flow of gas from the carburetor to the intake manil5 fold. Thus a turn buckle 2B, pivotally connected at one end to an arm 21 xed to the shaft 28 of the butterfly valve 5,*is pivotally secured at its opposite end to the piston rod 24. Hand throttle 6 is pivotally connected to an arm 29 on the shaft 20 28 of the butteriy valve through the medium of rods 30 and 30' respectively connected to opposite ends of a link 3l, .the latter being pivotally secured intermediate its ends to a front frame or part 32, by means of a bracket 60. A coil spring 25 33, connected at its respective ends to the cylinder I0 and turn buckle 26, normally moves the piston 23 toward the fluid I6 in cylinder Il) or to the right viewing Figure 1.

Cylinder I I is provided with a horizontally re- 30 ciprocable piston 34, actuated by a piston rod 35, extending reciprocably through the cover 36 of a housing or casing 31 for a centrifugal governor 38. The lower end of piston rod 35 is hollow for freely receivingthe upper end of an axially 35 aligned shaft 39, extending at its lower end through the bottom wall 40 of housing 31 and seated at its lower extremity in a roller bearing 4I, in turn supported in a gear case 42 secured to the bottom Wall 40, by bolts or other suitable fas- 40 teners 43. An adjusting screw 44 permits of -slight vertical adjustment of the roller bearing and shaft for the purpose of properly meshing gears 45 and 46. These gears are mounted respectively on and rotatable with the shaft 39 45 and a shaft 41, the latter carrying a pulley 48 driven by the fan belt 49, in turn preferably driven from the crank shaft of the automobile, not shown. A frame 50 for housing and supporting the centrifugal governor 38 is keyed to the shaft 39 as at 5I, and a threaded lock nut 52 is also provided for an obvious purpose.

I'he centrifugal governor 38 comprises a pair of opposltely arranged horizontally disposed weights 53 mounted for axial movement with 55 respect to shaft 39, on the bottom wall 54 of frame 50. Bell cranks 55, one for each weight, are rotatably secured to stub shafts 56 fixedly mounted in frame members 51. One arm 58 of.

each bell crank is bifurcated as at 59 forengagement with a pin 6I) in turn attached to weights 53, the bifurcations being free to swing in recesses '66 formed in the weights. A pair of springs 6| connect the two weights together. These springs 6|, one on each side of shaft 39, have their opposite ends connected to pins or posts 65 anchored in the outer ends of the weights. The other arm 62 of each lever 55, is pivotally connected to the lower end of an arm 63, the upper end of which is pivoted to a bearing member.64 in turn slidably but non-rotatably mounted on the shaft 39. The extent of outward radial movement of the weights 53 under the action of centrifugal force, when shaft 39 is roltated, is limited due to the resistance offered by the springs 6|. Fixed to the lower end of the piston rod 35 is a two part ball race collar 64', which cooperates with the bearing member 64 in an obvious manner. The two halves of the collar are suitably-secured to the rod 35 by means of screws 86.

In practice the operator advances the foot accelerator 1 in the usual way until the desired speed of travel is attained. Thereafter, the position of the accelerator is manually held fixed by the operator and the desired uniform speed will be automatically maintained,.lregardless of load, by the action of the governor 38, upon the hydraulic balancing system previously described, as will be presently understood. Forward movement of the foot pedal compresses spring 2| and causes the piston I8 to force the fluid I6 from cylinder 9, supply pipe I3 and branch pipe I4 into cylinder I6, against piston y23. The piston 23 and its associated rod is thus moved to a forward polsition against the tension of spring 33. The re.- sulting corresponding movement of turn buckle 26 and arm 21 causes the valve 5 to open and admit a correspondingly increased supply of gas from the carburetor to the intake manifold with consequent acceleration of engine speed. As the engine speed is increased the governor 33 moves the crank lever 55 in an anti-clockwise direction and the piston rod 35 and piston 34 will move downwardly, thus creating a suction upon and causing uid to be drawn from line I5, and thereby reducing the fluid content of cylinder I6.

vThe suction plus the action of spring 33 then slightly moves butterfly Valve 5, in an anticlockwise direction'or toward closed position, thereby retarding the flow of gasoline through the carburetor and maintaining R. P. M. practically constant.

When the car ascends a grade or the engine load is otherwise increased it of course becomes necessary to increase the fuel supply to prevent the speed from dropping lbelow the uniform minimum which the operator desires to rmaintain without further manual effort. As previously stated this is automatically accomplished through the medium of centrifugal governor 38. The R. P. M. of the governor shaft 39 coincides with Vthat of the motor due to the shaft and gear connection between the fan belt pulley 48 and the shaft 39. Consequently as the R. P. M. vof shaft 39 decreases by reason of increased load or hill climbing the weights 53 will move inwardly toward the axis of the governor under the action of springs 6|. As the bifurcations 59 of lever arms 58 engage pins 60 fixed to the weights 53.

the stub shafts 56 and the bell crank levers 55 are moved lin a clockwise direction thus elevating draulic fluid I6 thus dispelled from piston II, through lines I5 and I4 into piston III, causes piston 23 toopen valve` 5 suillciently to increase the R. P. M. the desired extent. The change in speed is slight and so quickly corrected as to insure a substantially uniform speed. By releasing all pressure from the foot pedal 1, spring 2| pulls the piston I8 rearwardly whereupon hydraulic fluid will be pulled by suction from lines I3 and I4 and cylinder I6 into cylinder 9, piston 23 and its associated rod being simultaneously moved in a rearward direction thus causing valve 5 to be rocked anti-clockwise to closed or idling speed position, This is aided by spring 33.

The capacity of cylinder between the high speed and low speed positions of its piston must be at least equal to but is preferably'approximately double that of cylinder I0, depending upon the degree of sensitivity desired, whereas foot accelerator cylinder 9, is slightly larger in operative area or capacity than cylinders Ill and Il combined, in order to take care of any leakage. The operative area or capacity of the system, including the cylinders and supply lines `must always be completely filled with fluid in order to be effective. Piston 34 in cylinder II completely controls action of piston 23 in cylinder I6 at all times, except when the operator applies pressure to or relieves pressure from the foot pedal during speed changing operations. Whereas after the desired speed has been attained and while the foot accelerator is kept in fixed position the action of piston 23 is controlled by the pumping action of piston 34, in turn actuated by the governor. The action of fluid in cylinder 9 controls the entire system because spring 2| is the master and strongest spring, that is, much stronger than spring 33. Springs 2| and 33 have no material effect on cylinder II, that is, their primary purpose is to control cylinder III only. It will' of course be understood that by increasing the size of cylinder II and its piston 34, the sensitiveness of the system can be correspondingly increased, that is, the range of R. P. M. variation can thus be reduced to the desired minimum. Should slight seepage occur the only affect on operation would be a slight change in the position of accelerator 1 and piston I8, both moving rearwardly to a slight extent. No bleeders are necessary as all lines and cylinders are arranged in a slightly inclined position to the horizontal in order that when shut off valve I1 is opened hydraulic uid will ow by gravity to the cylinders.

The forces exerted by hydraulic fluid against pistons 34 and 23 do not materially affect the action in cylinder as the springs 8| are very much stronger than spring 33, spring 33 being weaker than springs 6| and 2| is immediately affected by the action of pistons I8 and 34.

A conventional choke valve 62 is operated by a handle or knob 63 through the medium of rods 64 and 65, for controlling the admission of air tothe carburetor 2.

Having thus described my invention, what I claim is:

l. In a speed 4control mechanism for internal combustion engines having a throttle valve in the combustible mixture outlet of a carburetor, a shaft controlled by the speed of the motor, 'a throttle valve cylinder having a piston operatively connected to said valve, a foot accelerpiston rod 35 and its associated piston 34. Hy f ator, a master cylinder having a pistononera- 7| tively connected to said foot accelerator, a centrifugal governor having a shaft operatively connected with the said first mentioned shaft, a governor cylinder and piston and piston rod therefor, means connecting said piston rod with the governor shaft for actuating said governor piston, a supply tank for a relatively non-compressible fluid, a main and a branch supply pipe for supplying fluid from said tank to said master cylinder and to said throttle valve cylinder respectively, and another branch connected to said main supply pipe and said master cylinder for supplying fluid to said governor cylinder.

2. In a speed control mechanism for internal combustion engines having a throttle valve in the combustible mixture outlet of a carburetor, a shaft controlled by the speed of the motor, a throttle valve cylinder having a piston operatively connected to said valve, a foot accelerator, a master cylinder having a piston operatively connected to said foot accelerator, a centrifugal governor having a shaft operatively connected with said flrst mentioned shaft, a governor cylinder and piston and piston rod therefor, means connecting said piston rod with the governor shaft for actuating said governor piston, a supply tank for a relatively non-compressible fluid, a main and a branch supply pipe for supplying fluid by gravity from said tank to said master cylinder and to said throttle valve cylinder respectively, and another branch connected to said main supply pipe between said first mentioned branch and said master cylinder for supplying fluid by gravity to said governor cylinder.

3. In a speed control mechanism for internal combustion engines having a throttle valve in the combustible mixture outlet of a carburetor. a shaft controlled by the speed of the motor, a throttle valve cylinder having a piston operatively connected to said valve, a foot accelerator, a master cylinder having a piston operatively connected to said foot accelerator, a centrifugal governor having a shaft operatively connected with said first mentioned shaft, a Agovernor cylinder and piston and piston rod therefor, means connecting said piston rod with the governor shaft for actuating said governor piston, a supply tank for a relatively non-compressible fluid, a main and a branch supply pipe for supplying fluid from said tank to said master cylinder and to said throttle valve cylinder respectively, and another branch connectedto said main supply pipe between said first mentioned branch and said master cylinder for supplying fluid to said governor cylinder, the operative capacity of said master cylinder being approximately equal to the operative capacity ofthe remaining cylinders.

\4. In a speed control mechanism for internal combustion engines having a throttle valve in the combustible mixture outlet of the carburetor, a container for a relatively non-compressible fluid, a foot accelerator, a pair of oppositely disposed lcylinders and pistons therefor, one of said cylinders having a greater operative capacity than the other, a. supply pipe for supplying fluid from said container to said cylinders, the piston of said smaller cylinder being operatively connected to the throttle valve, the piston of larger cylinder being operatively connected to the foot accelerator, whereby forward movement of the accelerator forces fluid from said larger cylinder to said smaller cylinder to cause said throttle valve to open, a third cylinder connected to said supply pipe intermediate the connections of the u latter with said tlrsttwo mentioned cylinders, a

latar forces fluid from said larger cylinder to said centrifugal governor and shaft therefor controlled by the speed of the automobile and operatively connected with the piston of said third cylinder for drawing fluid from the smaller of said flrst two mentioned cylinders when the engine speed increases and permitting the piston of said smaller cylinder to move the throttle valve toward closed position.

5. In a speed control mechanism for internal combustion engines having a throttle valve in the combustible mixture outlet of the carburetor, a container for a relatively non-compressible fluid, a foot accelerator, a pair of oppositely disposed cylinders and pistons therefor, one of said cylinders having a greater operative capacity than the other, a supply pipe for supplying fluid from said container to said cylinders, the piston of said smaller cylinder being operatively connected to the throttle valve, the piston of said larger cylinder being operatively connected to the foot accelerator, whereby forward movement of the accelerator forces fluid from said larger cylinder to said smaller cylinder to cause said throttle valve to open, a third cylinder connected to said supply pipe intermediate the connections of the latter with said first two mentioned cylinders, a centrifugal governor and shaft therefor controlled by the speed of the automobile and operatively connected with the piston of'said third cylinder for drawing fluid from the smaller of said first two mentioned cylinders when the engine speed increases and permitting the piston of said smaller cylinder to move the throttle valve toward closed position, the operative capacity of said larger cylinder being greater than that of the remaining cylinders.

6. In a speed control mechanism for internal combustion engines having a throttle valve in the combustible :mixture outlet of the carburetor, a container for a relatively non-compressible fluid, a foot accelerator, a pair of oppositely disposed cylinders and pistons therefor, one of said cylinders having a greater operative capacity than the other, a. supply pipe for supplying fluid from said container to said cylinders, the piston of said smaller cylinder being operatively connected to the throttle valve, the piston of larger cylinder being operatively connected to the foot accelerator, whereby forward movement of the accelersmaller cylinder to cause said throttle valve to open and the engine to operate at desired speed, a third cylinder connected to said supply pipe, governing means controlled by the speed of the motor adapted to actuate the piston of said third cylinder for drawing fluid from the smaller of said first two mentioned cylinders when the engine speed increases beyond the desired maximum nndpermitting the piston of the cylinder of smaller capacity to move` the throttle valve toward closed position.

'7. In a speed control mechanism for internal combustion engines having a throttle valve' in the combustible mixture outlet of the carburetor, a foot accelerator, a pair `'of cylinders and pistons therefor, one of said cylinders having a greater operative capacity than the other, a source of supply for supplying a relatively non-compressible fluid to said cylinders, the piston of said smaller cylinder being operatively connected to said throttle valve, the piston of said larger cylinder being operatively connected to the foot accelerator, whereby movement of the accelerator forces fluid from said larger cylinder to said smaller cylinder to cause said throttle valve to open and the engine to operate at desired speed, a third cylinder connected to said source of fluid supply, governing means controlled by the speed of the motor adapted to actuate the piston of said third cylinder for drawing iluid from the smaller of said rst two mentioned cylinders when the engine speed increases beyond the desired maximum, thus permitting the piston of said smaller cylinder to move the throttle valve toward closed position.

8. In a speed control for internal combustion engines having a throttle valve in the combustion mixture outlet of a carburetor, a foot accelerator, a master cylinder having a piston operatively connected to the foot accelerator, a fluid system connected to the master cylinder for operating the throttle valve, and a centrifugal governor operated by the engine and operating a piston in said uid system maintaining the throttle valve in a position to maintain the speed set in the master cylinder previously set by the accelerator, regardless of the load on the engine.

9. In a speed control for internal combustion engines having a throttle valve in the combustion mixture outlet of a carburetor, a foot accelerator, a master cylinder having a piston operatively connected to the foot accelerator, a uid system connected to the master cylinder and operating a piston for operating the throttle valve, a centrifugal governor operated by the engine, and a piston in said fluid system operated by the governor for maintaining the speed set in the master cylinder by the accelerator, regardless of the load on the engine.

CHARLES HOLT. 

